Topband: [RFI] Powerline noise question

Frank W3LPL donovanf at starpower.net
Fri Dec 30 20:08:01 EST 2022


Rick,

You'll be very pleased with the performance of the WB8DSB RFI hunting
flag antenna.  

Don't forget to need lots of preamp gain. The WB8DSB flag is about 60 dB
down from a dipole on 160 meters. 40 dB of preamp gain is needed until
you're very close to the RFI source.

73
Frank
W3LPL

----- Original Message -----
From: "Richard" <richard at karlquist.com>
To: "Frank W3LPL" <donovanf at starpower.net>, "rfi" <rfi at contesting.com>, "PVRC" <pvrc at mailman.qth.net>, "topband" <topband at contesting.com>
Sent: Friday, December 30, 2022 8:25:47 PM
Subject: Re: [RFI] Powerline noise question

Thanks Frank.  You got me unstuck.
I have ordered the DX Engineering Kits and the PL330 receiver.

73
Rick N6RK

On 12/29/2022 7:53 PM, Frank W3LPL wrote:
> Hi Rick,
> 
> I recently built a WB8DSB man portable flag antenna (March 2021 QST)
> for RFI geolocation, its performance far exceeds my expectations.
> Its narrow deep null quickly, easily and definitively located the
> source of very troublesome 160 meter RFI to a single power pole
> more than three miles from my QTH.  Prior to constructing the
> flag antenna I could locate the RFI to only within a few hundred
> yards of the RFI source.
> 
> I built my flag antenna entirely out of materials I had on hand
> from previous projects including 3/8 inch diameter fiberglass rods,
> a pair of Advanced Receiver Research P1-30/20VD 20 dB HF preamps,
> a case of eight AA batteries to provide power to the preamps,
> a switchable attenuator and a Tecsun PL330 portable HF receiver.
> 
> I highly recommend this easily constructed RFI geolocation antenna
> for the toolkit of any serious HF operator.
> 
> 73
> Frank
> W3LPL
> 
> 
> 
> 
> 
> ----- Original Message -----
> From: "Richard" <richard at karlquist.com>
> To: "rfi" <rfi at contesting.com>
> Sent: Friday, December 30, 2022 3:15:32 AM
> Subject: [RFI] Powerline noise question
> 
> I have a powerline noise coming from about 2 miles away, which is
> nevertheless quite strong at my QTH.
> 
> Here are the symptoms:
> 
> 1.  A 120 Hz noise burst at regular intervals, about 0.9 seconds apart.
> 
> 2.  The noise goes away after a rain; then comes back after things dry
> out.
> 
> 3.  Can be heard from 500 kHz up to a few MHz.
> 
> 4.  The noise is very strong along a road for a few miles.  There is a
> 
> power line that follows the road.  I haven't been able to localize it
> better than
> 
> that so far.  From my QTH, though, it is definitely coming in at a
> specific azimuth
> 
> which is consistent with the noisy road a few miles away.  (Using a loop
> antenna
> 
> for DF'ing).
> 
> Any help appreciated.
>


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